In various manufacturing operations a power source, such as an electric motor, may drive a shaft which in turn drives an apparatus at a fixed speed. It will be understood that this speed could be changed by changing the speed of the motor, or by a speed changing gear box or the like between the motor and the shaft. However, by way of a specific example, it is often desired to have the speed of the driven apparatus remain constant. Nevertheless, it may be desirable from time to time to have the phase of the driven apparatus differ from the phase of the driving motor (or a gear box from the driving motor).
Prior art apparatus known to me for obtaining such phase adjustment suffers from excessive backlash.